Life Sciences Commons^™

Modeling The Acquisition Of Social Rank In Crayfish: Winner And Loser Effects And Self-Structuring Properties, Karlo Hock, Robert Huber

Robert Huber

No abstract provided.

How Costly Is It For Poor Farmers To Lift Themselves Out Of Subsistence, Laure C. Dutoit, Olivier Cadot, Marcelo Olarreaga

Olivier Cadot

The main objective of this paper is to provide estimates of the cost of moving out of subsistence for Madagascar's farmers. The analysis is based on a simple asset-return model of occupational choice. Estimates suggest that the entry (sunk) cost associated with moving out of subsistence can be quite large---somewhere between 124 and 153 percent of a subsistence farmer's annual production. Our results make it possible to identify farm characteristics likely to generate large gains if moved out of subsistence, yielding useful information for the targeting of trade-adjustment assistance programs.

The Caenorhabditis Elegans Heterochronic Regulator Lin-14 Is A Novel Transcription Factor That Controls The Developmental Timing Of Transcription From The Insulin/Insulin-Like Growth Factor Gene Ins-33 By Direct Dna Binding., Marta Hristova, Darcy Birse, Yang Hong, Victor R. Ambros

Victor R. Ambros

A temporal gradient of the novel nuclear protein LIN-14 specifies the timing and sequence of stage-specific developmental events in Caenorhabditis elegans. The profound effects of lin-14 mutations on worm development suggest that LIN-14 directly or indirectly regulates stage-specific gene expression. We show that LIN-14 can associate with chromatin in vivo and has in vitro DNA binding activity. A bacterially expressed C-terminal domain of LIN-14 was used to select DNA sequences that contain a putative consensus binding site from a pool of randomized double-stranded oligonucleotides. To identify candidates for genes directly regulated by lin-14, we employed DNA microarray hybridization to compare …

Climatic Unpredictability And Parasitism Of Caterpillars: Implications Of Global Warming, John O. Stireman Iii, Lee A. Dyer, D. H. Janzen, M. S. Singer, J. T. Lill, R. J. Marquis, R. E. Ricklefs, G. L. Gentry, W. Hallwachs, P. D. Coley, J. A. Barone, H. F. Greeney, H. Connahs, P. Barbosa, H. C. Morais, I. R. Diniz

Robert Marquis

The Three Dimensional Detection Of Microvasculatory Bed In The Brain Of White Rat Rattus Norvegicus By A Ca2+ -Atpase Method., Amaiak Chilingaryan, Amayak Chilingaryan, Gary Martin

Gary Martin

A procedure is described which allows for the selective and non-injectional staining of the three-dimensional microvasculatory bed (MVB) in thick sections (60–140 μm) of formalin-fixed brain tissue of white rats Rattus norvegicus. This histochemical method detects ATPase activity and takes place between pH 10.5 and 11.2. Calcium ion is used to capture inorganic phosphate, calcium phosphate is converted to lead phosphate, and subsequently converted to black or dark brown lead sulfide. All vessels are revealed due to a precipitate on the endothelium and smooth muscle cells of arterioles. In some vessels, red blood cells also stain. The background is transparent …

Silencing Of Retrotransposons In Dictyostelium By Dna Methylation And Rnai., Markus Kuhlmann, Branimira E. Borisova, Markus Kaller, Pontus Larsson, Dirk Stach, Jianbo Na, Ludwig Eichinger, Frank Lyko, Victor R. Ambros, Fredrik Soderbom, Christian Hammann, Wolfgang Nellen

Victor R. Ambros

We have identified a DNA methyltransferase of the Dnmt2 family in Dictyostelium that was denominated DnmA. Expression of the dnmA gene is downregulated during the developmental cycle. Overall DNA methylation in Dictyostelium is approximately 0.2% of the cytosine residues, which indicates its restriction to a limited set of genomic loci. Bisulfite sequencing of specific sites revealed that DnmA is responsible for methylation of mostly asymmetric C-residues in the retrotransposons DIRS-1 and Skipper. Disruption of the gene resulted in a loss of methylation and in increased transcription and mobilization of Skipper. Skipper transcription was also upregulated in strains that had genes …

Spiroplasma Penaei Sp. Nov., Associated With Mortalities In Penaeus Vannamei, Pacific White Shrimp, Linda M. Nunan, Donald V. Lightner, Marietta A. Oduori, Gail E. Gasparich

Gail Gasparich

Spiroplasma Leucomae Sp. Nov., Isolated In Poland From White Satin Moth (Leucoma Salicis L.) Larvae, Marietta A. Oduori, Jerzy J. Lipa, Gail E. Gasparich

Gail Gasparich

Callose (Β-1,3 Glucan) Is Essential For Arabidopsis Pollen Wall Patterning, But Not Tube Growth, Rob Swanson

Rob Swanson

Background: Callose (β-1,3 glucan) separates developing pollen grains, preventing their underlying walls (exine) from fusing. The pollen tubes that transport sperm to female gametes also contain callose, both in their walls as well as in the plugs that segment growing tubes. Mutations in CalS5, one of several Arabidopsis β-1,3 glucan synthases, were previously shown to disrupt callose formation around developing microspores, causing aberrations in exine patterning, degeneration of developing microspores, and pollen sterility. Results: Here, we describe three additional cals5 alleles that similarly alter exine patterns, but instead produce fertile pollen. Moreover, one of these alleles (cals5-3) resulted in the …

Problem Solving: A Foundation For Modeling, Janet Hodder, George Middendorf, D. Ebert-May

George Middendorf

No abstract provided.

Mesodermally Expressed Drosophila Microrna-1 Is Regulated By Twist And Is Required In Muscles During Larval Growth., Nicholas S. Sokol, Victor R. Ambros

Victor R. Ambros

Although hundreds of evolutionarily conserved microRNAs have been discovered, the functions of most remain unknown. Here, we describe the embryonic spatiotemporal expression profile, transcriptional regulation, and loss-of-function phenotype of Drosophila miR-1 (DmiR-1). DmiR-1 RNA is highly expressed throughout the mesoderm of early embryos and subsequently in somatic, visceral, and pharyngeal muscles, and the dorsal vessel. The expression of DmiR-1 is controlled by the Twist and Mef2 transcription factors. DmiR-1KO mutants, generated using ends-in gene targeting, die as small, immobilized second instar larvae with severely deformed musculature. This lethality is rescued when a DmiR-1 transgene is expressed specifically in the mesoderm …

Regulatory Functions Of Phospholipase D And Phosphatidic Acid In Plant Growth, Development, And Stress Responses, Xuemin Wang

Xuemin (Sam) Wang

No abstract provided.

Slip Sliding Away: Load-Dependence Of Velocity Generated By Skeletal Muscle Myosin Molecules In The Laser Trap, Edward P. Debold, Joseph B. Patlak, David M. Warshaw

Edward P. Debold

Skeletal muscle's ability to shorten and lengthen against a load is a fundamental property, presumably reflecting the inherent load-dependence of the myosin molecular motor. Here we report the velocity of a single actin filament translocated by a mini-ensemble of skeletal myosin ∼8 heads under constant loads up to 15 pN in a laser trap assay. Actin filament velocity decreased with increasing load hyberbolically, with unloaded velocity and stall force differing by a factor of 2 with [ATP] (30 vs. 100 μM). Analysis of actin filament movement revealed that forward motion was punctuated with rapid backward 60-nm slips, with the slip …

Graduate Colloquium, Borbala Mazzag

Borbala Mazzag

No abstract provided.

Evolutionary Innovation: A Bone-Eating Marine Symbiosis, Shana K. Goffredi, Victoria J. Orphan, Greg W. Rouse, Linda Jahnke, Tsegeria Embaye, Kendra Turk, Ray Lee, Robert C. Vrijenhoek

Shana Goffredi

Symbiotic associations between microbes and invertebrates have resulted in some of the most unusual physiological and morphological adaptations that have evolved in the animal world. We document a new symbiosis between marine polychaetes of the genus Osedax and members of the bacterial group Oceanospirillales, known for heterotrophic degradation of complex organic compounds. These organisms were discovered living on the carcass of a grey whale at 2891 m depth in Monterey Canyon, off the coast of California. The mouthless and gutless worms are unique in their morphological specializations used to obtain nutrition from decomposing mammalian bones. Adult worms possess elaborate posterior …

Androdioecy Inferred In The Clam Shrimp Eulimnadia Agassizii (Spinicaudata : Limnadiidae), Stephen Weeks, Ryan Posagi, Michele Cesari, Franca Scanabissi

Stephen C. Weeks

Androdioecy (mixtures of males and hermaphrodites) is a rare mating system in both the plant and animal kingdoms. Androdioecy has been described in three branchiopod species, and is best known from the clam shrimp Eulimnadia texana Packard. Herein we describe sex ratio, genetic and histological evidence from the clam shrimp Eulimnadia agassizii Packard that suggest androdioecy is also found in this species. The E. agassizii population sampled had all-females, and when these females were isolated and allowed to produce eggs, those eggs yielded 100% female offspring in 15 out of 15 cases. Additionally, the originally isolated females proved to be …

Digenic Control Of Colouration In The Two-Spot Gourami Trichogaster Trichopterus Trichopterus, Jack Frankel

Jack Frankel

Paramyosin Phosphorylation Site Disruption Affects Indirect Flight Muscle Stiffness And Power Generation In Drosophila Melanogaster, Hongjun Liu, Mark S. Miller, Douglas M. Swank, William A. Kronert, David W. Maughan, Sanford I. Bernstein

Mark S. Miller

The phosphoprotein paramyosin is a major structural component of invertebrate muscle thick filaments. To investigate the importance of paramyosin phosphorylation, we produced transgenic Drosophila melanogaster in which one, three, or four phosphorylatable serine residues in the N-terminal nonhelical domain were replaced by alanines. Depending on the residues mutated, transgenic lines were either unaffected or severely flight impaired. Flight-impaired strains had decreases in the most acidic paramyosin isoforms, with a corresponding increase in more basic isoforms. Surprisingly, ultrastructure of indirect flight muscle myofibrils was normal, indicating N-terminal phosphorylation is not important for myofibril assembly. However, mechanical studies of active indirect flight …

Effect Of Des-Aspartate-Angiotensin I On The Actions Of Angiotensin Ii In The Isolated Renal And Mesenteric Vasculature Of Hypertensive And Stz-Induced Diabetic Rats, Dharmani Devi A/P Murugan

Dharmani Devi A/P Murugan

The present study investigated the action of des-aspartate-angiotensin I (DAA-I) on the pressor action of angiotensin II in the renal and mesenteric vasculature of WKY, SHR and streptozotocin (STZ)-induced diabetic rats. Angiotensin II-induced a dose-dependent pressor response in the renal vasculature. Compared to the WKY, the pressor response was enhanced in the SHR and reduced in the STZ-induced diabetic rat. DAA-I attenuated the angiotensin II pressor action in renal vasculature of WKY and SHR. The attenuation was observed for DAA-I concentration as low as 10(-18) M and was more prominent in SHR. However, the ability of DAA-I to reduce angiotensin …

Gender Differences In Lower Extremity Coupling Variability During An Unanticipated Cutting Maneuver, Joseph Hamill, Bryan C. Heiderscheit, Christine D. Pollard

Joseph Hamill

The purpose of this study was to determine if gender differences exist in the variability of various lower extremity (LE) segment and joint couplings during an unanticipated cutting maneuver. 3-D kinematics were collected on 24 college soccer players (12 M, 12 F) while each performed the cutting maneuver. The following intralimb couplings were studied: thigh rotation (rot)/leg rot; thigh abduction-adduction/leg abd-add; hip abd-add/knee rot; hip rot/knee abd-add; knee flexion-extension/knee rot; knee flx-ext/hip rot. A vector-coding technique applied to angle-angle plots was used to quantify the coordination of each coupling. The average between-trial standard deviation of the coordination pattern during the …

Quasistatic And Continuous Dynamic Characterization Of The Mechanical Properties Of Silk From The Cobweb Of The Black Widow Spider Latrodectus Hesperus, Todd A. Blackledge, John E. Swindeman, Cheryl Y. Hayashi

Todd A. Blackledge

Spider silks are among the strongest and toughest known materials, but investigation of these remarkable properties has been confined largely to orb-weaving spiders. We investigated the mechanical performance of silk from the cobweb-weaving spider Latrodectus hesperus. Both silk from the scaffolding region of the web and sticky gumfooted capture lines had material properties similar to the major ampullate silk that orb weavers use as the framework for their orb webs. Major ampullate fibers obtained from anaesthetized Latrodectus spiders were similar, but exhibited increased stiffness and reduced extensibility. Novel continuous dynamic analysis of the silks revealed that the loss tangent (tan …

High Speed Flight At Low Altitude - Hazard To Commercial Aviation?, Paul F. Eschenfelder

Paul F. Eschenfelder

No abstract provided.

A Multidimensional Approach For Detecting Species Patterns In Malagasy Vertebrates, Anne D. Yoder, Link E. Olson, Carol Hanley, Kellie L. Heckman, Rodin Rasoloarison, Amy L. Russell, Julie Ranivo, Voahangy Soarimalala, K. Praveen Karanth, Achille P. Raselimanana, Steven M. Goodman

Amy L. Russell

The Importance Of Experimental Design In Proteomic Mass Spectrometry Experiments: Some Cautionary Tales, Jeffrey S. Morris, Jianhua Hu, Kevin R. Coombes, Keith A. Baggerly

Jeffrey S. Morris

Proteomic expression patterns derived from mass spectrometry have been put forward as potential biomarkers for the early diagnosis of cancer and other diseases. This approach has generated much excitement and has led to a large number of new experiments and vast amounts of new data. The data, derived at great expense, can have very little value if careful attention is not paid to the experimental design and analysis. Using examples from surfaceenhanced laser desorption/ionisation time-of-flight (SELDI-TOF) and matrix-assisted laser desorption–ionisation/time-of-flight (MALDI-TOF) experiments, we describe several experimental design issues that can corrupt a dataset. Fortunately, the problems we identify can be …

Qualidade Da Água Da Nascente De Anços (Serra De Sicó) Com O Uso De Fitoperifiton, Ana Sofia P.S. Reboleira

Ana Sofia P.S. Reboleira

O estudo diatomológico da nascente do Rio Anços (Serra de Sicó), foi efectuado sazonalmente, entre o Verão de 2002 e o Outono de 2004. Escolheu-se uma estação de colheita, na parede da nascente exposta à água que provém do interior do Maciço. Com o intuito de monitorizar a qualidade da água, foram recolhidas diatomáceas perifíticas. Condutividade, pH, temperatura e oxigénio dissolvido foram medidos na estação em cada colheita efectuada. Vinte e sete espécies, distribuídas por dezasseis géneros foram observados. Cocconeis placentula Ehrenberg var. lineata (Herenberg) Van Heurck foi a espécie dominante, seguida de Navicula minima Grunow, N. cryptotenella Lange-Bertalot, Gomphonema …

What Communities Should Do Pre-Event To Support Public Health Post-Event Assessments, Surveillance And Monitoring, Thomas Lyons Carr Iii

Thomas Lyons (Thom) Carr III Appl.Sc., CEM

[Abstract written March 2008, TLC] Under worst-case planning assumptions used by some major metropolitan areas, a Neighbor-to-Neighbor self-help program model is the primary link between citizens and the professional response personnel of the responsible government agencies.

In the Neighbor-to-Neighbor self-help program model or a Community Emergency Management Plan (CEMP) calls on the citizens in neighborhoods to identify and establish cluster emergency preparedness committees, Cluster Emergency Coordination Centers (CECC) and Community Emergency Response Teams (CERT). Missing from these plans or what is not articulated is how constant Public Health Post-Event Surveillance, Monitoring and Assessments will be done. Given the worst-case planning …

Biogeography Of The Nearshore Rocky-Reef Fishes At The Southern And Baja California Islands, Daniel Pondella, Brooke Gintert, Jana Cobb, Larry Allen

Daniel Pondella

No abstract provided.

Interaction Between The Dorsal And Ventral Pathways In Mental Rotation: An Fmri Study, Hideya Koshino, Patricia Carpenter, Timothy Keller, Marcel Just

Marcel Adam Just

No abstract provided.

Imagining Material Versus Geometric Properties Of Objects: An Fmri Study, Sharlene Newman, Roberta Klatzky, Susan Lederman, Marcel Just

Marcel Adam Just

No abstract provided.

Functional Connectivity In An Fmri Working Memory Task In High-Functioning Autism, Hideya Koshino, Patricia Carpenter, Nancy Minshew, Vladimir Cherkassky, Timothy Keller, Marcel Just

Marcel Adam Just

No abstract provided.